Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 17)
17.
The maximum diameter of the hole that can be punched from a plate of maximum shear stress 1/4th of its maximum crushing stress of punch, is equal to (where t = Thickness of the plate)
t
2t
4t
8t
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
65 comments Page 3 of 7.

Bidhan Das said:   7 years ago
The answer will be d=t.

Ravikumar said:   7 years ago
The Answer is d = t.
Because shear stress = 1/4 crashing stress.
Now,
p/(πdr) = p/(πdd/4)4.
d=t.

Aarif said:   7 years ago
d = t is the right answer.

Nitesh said:   7 years ago
Here, d= t is the right answer.

Ramkumar said:   8 years ago
According to me, the correct answer is "d=t" only!

Sachin Sharma said:   8 years ago
I also agree with d=t

Beacuse, shearing stress is given 1/4th of crushing stress hence and shearing force is calculated by shearing stress into the shearing area and hence shearing area is (π/4 d^2) x t Hence shearing force will be,
(πd) x t x (shearing stress)
and crushing stress of punch will be equal to π/4 d^2) x σc
now (πd) x t x (σc/4) =π/4 d^2) x σc

Hence after solving d=t.

Balu said:   8 years ago
d = t is right answer.

Bharadwaz said:   8 years ago
Almost all are saying using shear in rivets formula,
But in question it is mentioned punching so shear is load(p)/area(pi*d*t).
Shear stress = P/pi*D*t.
Crushing stress = 4*P/pi*D*D,
Shear=crushing/4,
P/pi*D*t.=(4*P/pi*D*D)*(1/4),
P/pi*D*t=P/pi*D*D,
d=t.

Shubham Soni said:   9 years ago
Shear stress = P/π/4 * D^2 = 4P/π.D^2.
Crushing Stress = P/D.t.
So, Shear stress = 1/4 of Crushing Stress.
Therefore, 4P/pi.D^2 = P/D.t.
Hence, 4/pi. D = 1/t.
D = 4t/π.
i.e. D is directly proportional to the 4t.
Hence the answer is 4t.

Neeraj said:   9 years ago
@Akahai.

7.62 apply same formula and this answer of questions is D=tCrushing force = shearing force.
==> σ [(φ/4)* D^2] = τ[φD t].


Post your comments here:

Your comments will be displayed after verification.